<style>
  .line strong {
    color: black;
  }
  .line {
    color: transparent;
    --line-width: 100%;
    position: relative;
    background-color: rgba(0, 0, 0, 0.3);
    background-image: linear-gradient(
      90deg,
      hsla(0, 0%, 0%, 1),
      hsla(0, 0%, 0%, 1) var(--line-width),
      hsla(0, 0%, 100%, 0) var(--line-width)
    );
    background-clip: text;
  }
</style>